Mechanical Properties of Self-compacting Concrete Containing Fine Aggregates from Cement Kiln Dust and Hardened Cement Waste

Abstract

The aim of this research is to assess the mechanical performance of self-compacting concrete containing different percentages of fine aggregates, produced from the wastes generated by the cement plant industry and construction sites. Eight mixes, incorporating cement kiln dust (CKD) and hardened cement waste with partial fine aggregate replacement of 5%, 10%, 15%, and 20%, were produced and compared with a control mix made with 100% of crushed sand. The workability properties (e.g., flowability, passing ability, and resistance to segregation) and mechanical properties (e.g., compressive, flexural, and splitting tensile strengths) of all mixes were evaluated. The results showed that concretes containing recycled fine aggregates proved to have the best mechanical properties, compared to one made with crushed calcareous sand. However, self-compacting concrete with high mechanical strength could be produced with up to 15% wt. CKD replacement and with 10% wt. hardened cement waste replacement.

General analysis of the dissipation of strain energy in circular columns

“…This is due to the hydrated products formed by the addition of CS, particularly the entanglement of C-S-H gel, which gives strength to SCC and develops on the surface of unhydrated grains, gradually filling the capillary voids between the grains and resulting in densification of the matrix. This explains the lower water absorption of SCC compared to SCG (Granite Sand Concrete) [24]. As consequence, these results have shown to be consistent with those found by Ahmadi et al [44] and Ghorbani et al [45].…”

“…However, this increase in density is expected because recycled sands have higher absolute densities, higher quantities of fines filling the available voids between the concrete constituents and higher water absorption coefficients than ordinary sand. Therefore, these results are compatible with those found by Abukersh and Fairfield [23] and Kherraf et al [24] and contrary to those obtained by Shamsabadi et al [25]. This difference in results may be linked to the different particle distribution and the method of obtaining recycled sand.…”

“…At 28 and 90 days, concretes based on recycled clinker sand give the best compressive strengths compared with concretes based on granite waste sand. Nevertheless, this is due, on the one hand, to the fineness modulus of the CS sand and, on the other hand, to the presence of CaO, which provides a lot of C3S, an element responsible for strength and cohesion [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. There was a good linear correlation (Fig.…”